MONTGOMERY -- The top executive of the Alabama Education Association teachers' lobby today said he's urging people to vote yes on Tuesday's referendum in part to protect the Education Trust Fund, the main source of state money for public schools and colleges.

AEA Executive Secretary Henry Mabry said he fears that if voters say no, legislators in coming months might try to take money from the Education Trust Fund to fill a hole in the General Fund.

He also said a no vote could endanger funding for Medicaid, which provides health care to 940,000 disabled and low-income Alabamians.

''There are two reasons why the education community needs to support this: One, doing what's right for our poor people and providing necessary services, and two, taking away any kind of incentive that lawmakers may have to try to come backfill any hole with education dollars,'' Mabry said.

A yes vote on Tuesday would rewrite the state constitution to make special transfers of $145.8 million a year in each of the next three fiscal years from the Alabama Trust Fund to the General Fund.

The proposed amendment also would change the decades-old way that regular annual transfers of interest or other funds are made to the General Fund from the trust fund, which now has $2.3 billion in invested assets and now collects most of the royalties paid the state by companies that pump natural gas offshore.

Opponents of the amendment say legislators should make government more efficient and able to live within its means without raiding the Alabama Trust Fund.

The proposed amendment does not require repayment of the $437.4 million in special transfers. If the referendum passes, the Alabama Trust Fund could be that much smaller than it otherwise would have been about three years from now.

The smaller the trust fund, the less money it likely could give the General Fund in regular, annual payments in coming decades.

''There are two primary problems we see with the amendment. Number one, there's no provision for repayment. And number two, there are other viable options,'' said Chris Isaacson, executive vice president of the Alabama Forestry Association.